Patent document 1: JP-A-2003-153588
A conventional motor control apparatus controls a driving of a motor having multiple winding sets with multiple power inverter circuits. In addition, the apparatus has a temperature sensor to detect a temperature of a power switching element that receives large electric current, the temperature sensor being provided near the power inverter circuit. The apparatus monitors an abnormal heat generation in the power switching element.
For example, in a motor driving apparatus described in patent document 1, temperature sensors provided in or near power modules of two inverter circuits detect the temperature of the power module respectively. When a temperature by a calorific value of one of the power module exceeds a temperature threshold, an inverter circuit connected to a motor is switched over to the other of the power module.
The applicant of the present disclosure has found the following.
In the apparatus of patent document 1, a temperature abnormality is determined whether the temperature value of the power module exceeds the temperature threshold, from only an absolute viewpoint. In this determination manner, as long as the temperature value is in an allowable temperature range to the temperature threshold, a slight abnormality that is somewhat deviated from an originally desired condition may not be detected.
For example, in a manufacturing process of an apparatus, it is supposed that an application state of a heat radiation gel applied between an element and a heat sink in two systems of power inverter circuits has variation. In this case, since a difference in a radiation performance of the two systems of the power inverter circuits exists, this may not be a preferable state. However, when the temperature of the two systems of the power inverter circuits are in an allowable temperature range absolutely (that is, from the absolute viewpoint), it may be determined with a normal state according to a conventional technology.